The operation control of an assembling robot and a conveying robot is programmed and executed under a state of grasping and specifying the position and posture of an object (workpiece) based on a robot coordinate system based on the robot mechanism, or the like.
On the other hand, information such as the position and posture of workpieces to be assembled or conveyed and the position of obstacles or the like in the state that the robot does not grasp them is specified based on an outer coordinate system in a static space different from the robot coordinate system such as a world coordinate system and an object coordinate system, for example.
Accordingly, when assembly and conveyance are performed using a robot, the relationship between the robot coordinate system and the external coordinate system needs to be grasped or specified previously. Note that the relationship between the robot coordinate system and the external coordinate system is represented by a coordinate transformation matrix (row and column) of the robot coordinate system and the external coordinate system from a mathematical standpoint.
As a method for specifying the relationship between the robot coordinate system and the external, coordinate system, a method of grasping it by mounting an exclusive jig, a touch sensor, etc. on a robot hand, other than that, a method of using a visual sensor or the like are known, conventionally (Patent Document 1, for example).
However, in the method using the exclusive jig, the teaching operation is manually performed and requires skill and time. Also, the method of using the visual sensor or the like has problems that the measuring accuracy is subject to the environmental light and the hand becomes heavy.
Moreover, particularly when the method of using the exclusive jig and the touch sensor is applied to the robot which handles semiconductors, it may be a cause of generation of dusts and particles due to contact with workpieces or the like since they are used in a clean environment.